1. Field of the Invention
This invention relates generally to a double isolated jounce bumper system for use in wheel suspensions for motor vehicles.
2. Disclosure Information
Automotive suspension systems almost universally include mechanisms which permit the roadwheels to travel upward in a direction toward the vehicle's body in the event that an obstruction is encountered in the roadway. Although such vertical displacement of the roadwheels is a desirable characteristic of a suspension system, provisions must be made within the system to limit the maximum displacement in an upward direction. This limitation is typically imposed upon the suspension system by an elastomeric snubber most often termed a "jounce bumper". The term "jounce" refers to movement of the suspension in an upward direction. Thus, "full jounce" means that the suspension is in its uppermost position wherein part of the suspension impinges upon the jounce bumper.
Jounce bumpers have been in wide use for many years in motor vehicles and have been mounted on suspension arms as in U.S. Pat. No. 2,179,856, or upon the chassis or body as in U.S. Pat. Nos. 2,660,449, and 3,149,855. U.S. Pat. No. 3,111,307 discloses yet another construction in which bumpers are mounted to both the chassis and to a lower control arm. In German Pat. Nos. 1,170,257 and 1,924,175, a jounce bumper mounted upon a frame member contacts a concave section formed in a control arm during full jounce.
In the case of the present invention, a jounce bumper system comprises two elastomeric bumpers having rigid cores and complementary, nesting shapes. The two constituent bumpers may be incorporated into spring isolators for coil spring equipped suspensions. The present jounce bumper system is double isolated because unlike conventional systems in which an elastomeric bumper directly contacts a frame member or the like during full jounce, the present system always maintains a rubber-to-rubber contact. This is advantageous in that the ride harshness of the vehicle may be reduced and the life of the jounce bumper system increased.